The 3 Step "MPG Solution" 

1. Vehicle maintenance
2. Driving methods and tips
3. Fuel savings devices and vehicle modifications

Here are the 3 steps we recommend for getting the most from your gallon of fuel. Of course, each step consists of many "baby steps" that are all very important.  Keep reading below to get details for each step.   I have personally managed improvements of 35% just using steps 1 and 2 in my 1994 Toyota 2WD Pickup.  I have had MPG readings as low as 22 mpg on the highway. I was driving fast and climbing hills.  I have had MPG readings just over 31 mpg and now average about 29 MPG when I consistently follow step #2.  This was achieved by changing driving habits like avoid heavy braking, coast to stop lights, slower acceleration, and slower top speeds.  Eliminating unnecessary weight has helped achieve about 15-20% of the increase.  The truck had a work rack installed and when that was removed I instantly got another 4-5 MPG.  Driving methods and proper maintenance netted an additional 3-5 mpg in my case.  I can alter the MPG in my 1994 Infiniti Q45 by 20% from one fill up to the next by only employing step #2 for a tank of fuel.  All of the percentages I've estimated are only that, estimates. You will see many different estimations on the amount of saving you can get from any one tip as they will vary from car  to car and driver to driver.  You'll just have to try it to get your own numbers.  Good luck and be consistent and persistant!

Don't miss the MotorWeek video on driving styles and how they affect MPG.
One of my mileage logs- July '06 thru Aug. '06 in 1994 Infiniti Q45

1. Vehicle maintenance (1-10% increase or more depending on the condition of your vehicle)

• Check tire pressures: Can add about 3%.  Add 2 PSI to the recommended PSI and you could get an additional 1 MPG. Some use tire pressures up to 40-50 PSI but I wouldn't suggest going to high over the recommended pressure. You can make the car unsafe as well as causing premature tire wear which will force you to purchase new tires early.  This would eat up some, or all, of your savings from increasing the PSI in the first place.  I have seen many vehicles that had tire pressures as low as 10-15 PSI because the owner never checked their tire pressure.  You should check it at least once per week. Pressures will vary with temperature and altitude changes.  "Under-inflated tires can lower gas mileage by 0.4 percent for every 1 psi drop in pressure of all four tires" according to fueleconomy.gov.
   
• Keep your engine tuned up: Can save about 5-10%.  Change oil regularly, I prefer synthetic but as long as you change it frequently you will be fine with standard oil.  Change or clean the air filter regularly, your engine will have to work harder to pull air through a dirty filter.
   
• Address any mechanical issues quickly, if you have a check engine light, chances are your vehicle is not going to be running at 100% efficiency. You could have problems with your fuel system, ignition system, oxygen sensor, EGR valve, vacuum system, and other things.  All of these issues can effect your MPG.
   
• Have your alignment checked and adjusted.  An improperly aligned vehicle will have additional drag and can greatly reduce your MPG.  Uneven tire wear is an indicator you need an alignment but by the time your tires wear unevenly it's been a problem for a long time.  Have it checked before you think there is a problem.  Also, catching problems early will save you repair costs.
   
• Check your brakes. Make sure they don't drag and put an extra load on the engine.
   
• Don't haul around unnecessary junk.  This can save you 1-2% per 100 lbs. Many people, including myself, over time accumulate a lot of extra stuff in their vehicles.  This junk can easily add 100 pounds or more to your vehicle. It takes power to haul that weight around.  Clean out that junk!
   
• Some vehicles have accessories that are not necessary or are only needed some of the time. Remove those items until they are needed.  Examples would include service racks on trucks, winches on off road vehicles, large tool boxes in trucks, and cargo "pods" or racks on cars. In addition to the weight, some add wind resistance which will also effect your MPG.  Just take a look at your vehicle and decide if there is anything on it you could remove that isn't needed.  Obviously, you wouldn't want to remove any safety items like bumpers so be smart about what you do.

2. Driving methods and tips (5-33% increase potential, most of these take a lot of discipline)

• Accelerate smoothly and slowly up to your cruising speed and maintain it with cruise control, if you have it.  You're not in a race so take it easy.  You'll save fuel and maybe even a speeding ticket!
   
• Keep it at 55 mph or under.  This can save you 7-23%. Wind resistance over that really eats up fuel.  Obviously, there are freeways with a speed limit of 65-75 mph so you don't want to be a road hazard to other drivers.  I'll take it to 65 mph on these roads but occasionally have to speed up a bit.  Be courteous in your quest for more mileage and don't risk triggering someone's road rage by driving to slowly and blocking traffic, it's not worth it.  The graph below shows how your MPG varies with speed.  You can see that 50-55 mph will typically net you the max MPG.
  
   
• Pick the right car for the job.  What I mean by this is if you have several cars use the most economical one for the trip you are taking.  Don't take your big SUV 50 miles to work with just you in it, leaving your little Honda civic at home for your wife to drive with the 3 kids 5 miles to the store or to school.  Swallow your pride and drive that little "econo-box" to work.  You'll save hundreds of dollars and that's no exaggeration. I have a Toyota pickup I drive most of the time and once or twice a week I "treat" myself to the luxury car. I save a bundle, put less wear and tear on my nice car, and I also appreciate car much more when I drive it.
   
• Avoid driving to work during rush hour if you have some flexibility with your schedule.  Sitting in stop and go traffic wastes huge amounts of fuel. Go to work earlier then leave earlier to avoid the traffic, or go in later and come home later.  In my case it's usually go in earlier and come home later. You will maintain your sanity better not having to sit in traffic and your boss will love it.  You might even get a raise!  Whatever you can do, just stay out of that traffic jam. Obviously, not driving increases your MPG 100% so work from home if you have the option, if only a day or two a week.
   
• Avoid using the air conditioning unless you really need it.  Here in Arizona it's not really a choice during the summer, it's a must have.  If you are in a hot climate your only hope during the summer might be to refer to the tip above.  Driving earlier or later when it's not as hot will allow you to keep the a/c off.  Unfortunately for me, my Toyota pickup doesn't have a/c at all so I am forced to park it for the really hot summer months and drive the car that gets 1/2 the mileage.  There are still ways to use a/c and make it more efficient.  Every 10 minutes or so you can turn off the compressor (a/c button) and the vents will blow cold air for a few minutes. So you could do 10 minutes ON 5 Minutes OFF for example.  On a 1 hour commute that would have your a/c OFF for a total of 20 minutes.  You should remain quite comfortable and will save some money. Keep the controls on the "Recirculate" setting, if you have it, so you don't pull in hot air while the a/c is OFF.  The blower will be circulating the air inside the vehicle that is already cooled down quite a bit.  The a/c compressor takes about 8 horsepower to run it and that eats gas.
   
• A/C vs. windows down.  This one is controversial and an ongoing debate. I personally think it would use more to have the a/c on.  It probably depends on the vehicle and speed.  Different vehicles have different aerodynamics that could vary the results greatly.  There is a story on the articles page that talks about this more and has peoples comments and thoughts on the subject from their experiences.  I honestly can't speak from experience as I haven't ever tried it.
   
• Tailgate UP or DOWN.  This one is also controversial but I do have some experience with this one.  In my Toyota P/U I was able to get a 1 MPG average increase by lowering my tailgate.  Others have tested this and claim it hurt their MPG.  The Mythbusters did some tests and they found that it hurt mileage on the Ford full size pickups they were using.  You will just have to try it on your own to see if it helps you.  I think it depends on the vehicle.
   
• Braking.  I am a believer in this one. I think this can easily be the single biggest fuel saver on the list, at least for me with my typical commute.  Some vehicles may do better leaving the vehicle in gear and coasting while others will do better in neutral.  My Toyota P/U does better in neutral.  I drive about 75 miles per day about 60 % city 40% highway.  I have to start and stop many times during my commute.  I have found that at roughly 50-60 mph my vehicle will coast in neutral for at least a mile.  Now I can't usually coast that far because I'd be going too slow as I approached the intersection and would usually make people mad at me.  Plus, you really have to get used to judging distance to know when to put it in neutral.  I have taken odometer readings and for a majority of my stops, or instances where I have to slow down, I can coast at least 1/3-2/3 of a mile for each stop I make.
  
  This means on my commute I can typically coast from 3-6 miles out of 37.  During coasting you are getting very high MPG!  This can easily add up when you get good at it.  The less you use your brakes the more miles you will get out of your gallon of fuel.  For example, say you accelerate from a stop light and reach 45 mph half way to the next light. If you continue at 45 mph until you are forced to hit the brakes at the next light you used enough fuel to probably make it another mile or so.  Instead, you converted that energy to heat by using the brakes hard.  Now lets say you start from the same light, reach 45 mph half way there and put it in neutral and coast to the next light only having to use the brakes to slow from say 15-25 mph.  You now used much more of the fuel you burned to travel more miles.
  
  The reason some vehicles may do better leaving it in gear is because the fuel is cut off while coasting.  Even so, the extra distance you may be able to coast in neutral versus in gear may make up the difference.  You'll have to do your own experiments to find out which is best for your vehicle.  To make a long story short, use the brakes as little as possible regardless of whether you leave it in gear or not.  The more you use the brakes the more fuel you will waste.   If you want to get really crazy you can shut off the engine for long coasts as well but BE CAREFUL!  If your vehicle has power brakes and steering you will loose them.  Also, if you turn the key too far the STEERING WHEEL WILL LOCK!  It's not really a good idea to shut off the engine although I have done it on occasion. 
   
• Drafting.  No, I don't mean like in NASCAR, NO BUMP DRAFTING!  Following big trucks, even a relatively safe distance back, will reduce the wind resistance on your vehicle.  Not much to talk about on this one except use common sense, don't follow too closely, and DON'T TAILGATE!  You will eventually tailgate Mr. Roadrage and he'll slam on the brakes and run you off the road.
   
• Plan ahead.  Planning trips to the store so you avoid multiple trips.  Also, plan your route so you don't go extra miles.  Stop at the store on your way home from work to avoid having to go back out.
   
• Shop for best fuel price. There are several web sites that give you the gas prices, hi and low, for your area.  If you know what's the lowest in town, you'll know if the station you stopped at has a good price or not.  On the left side of our page you will see the average price for a gallon of unleaded and premium fuel for your area.  This can give you a ballpark to go by.  Try and find fuel below the average and you are doing pretty good.  Keep track of the prices of the stations you pass on your commute so you can pick the cheapest one. I wouldn't recommend driving across town to save $.08-.10 on a gallon because you'll use up the savings driving there and back.  Just find the best deal on your particular commute.

3. Fuel savings devices and vehicle modifications

• Step 3 is very controversial but we are confident that there are some effective devices available, or
  will soon become available and we hope to be there to prove, or disprove, that they do what we all hope they will....increase our MPG!  I think it is silly when people say there is nothing that will help your mileage significantly.  As fast as technology is advancing it is only a matter of time before someone makes a major breakthrough, it could even be you!  It is true, however, that most of the products on the market currently are nothing more than gimmicks so buyer beware!
   
• There are many that the EPA tested that are listed on the Product Test page.  Nearly all of them were not effective at all.  If you are one that believes there is a conspiracy then you should conduct some of your own tests.  I've already seen through my own tests that there are methods that one person finds ineffective another is successful with.  We will be doing some of our own tests as we acquire products.  We will be doing on the road real life tests but it's more difficult to get really accurate data that way.  The EPA was supposedly using a dynamometer under very controlled, duplicatable conditions.
   
• Hydrogen on Demand or HOD.  This is one that is not on the EPA list, at least that I can find, and many are selling and swearing by it.  They are all over the internet and e-bay.  They use electrolysis to generate hydrogen and oxygen gas from water.  The gas is then vented into the intake manifold of your car.  The claim is that the hydrogen/oxygen gas will supplement your fuel causing your engine to burn less gasoline.  I have found several units that appear to be very good quality and dozens that appear to be....well...junk for lack of a better word. Practically anyone could build one of these in their garage in a day and that is what it seems some people are trying to peddle on e-bay, so again, buyer beware.  Don't expect too much if you buy one over e-bay.  It will probably work but whether it works well enough to install in your car and give you better MPG is another story.  We have already build a working prototype of one of these "HOD Reactors" and it does, in fact, generate combustible hydrogen gas from water.  There are a lot of issues that I feel must be sorted out before I will put it in a vehicle but I am optimistic that this technology can and will continue to evolve.  Vehicles can be run entirely on hydrogen so it only seems logical that it could be used as a supplemental fuel system working in parallel with gasoline to aid in combustion.  I will be posting some video clips of our experiments for you to see it in action.  One issue will be making sure the computer leans out the fuel properly when you provide hydrogen to the mix.  This can be accomplished with some electronics circuits which we are already working on. They basically trick your computer into leaning out the mixture by altering the signal coming from the O2 sensor.  Hydrogen technology, and it's support systems, are our primary focus at this time so you can expect to see more information on this soon.  We will likely have an entire page, or more, devoted to hydrogen.  If you couldn't already tell, we are excited about hydrogen!  If it turns out not to work well in a car, the device will still be fun at parties.  It'll make a heck of a bomb out of a zip lock baggie and it's fun to shoot water bottles across the yard!
   
• Update on our HOD project. We are underway with the development of two HOD models.  These will be 7 cell models and should prove to be very effective and efficient.  More details will be posted shortly.  We will be offering individual parts for those that would like to experiment for themselves as well as complete turn key units.
   
• EFIE (Electronic Fuel Injection Enhancer).  Here is one device you must have!  This unit offsets the signal going from your O2 sensor to the ECU.  The ECU will lean the fuel mixture and allow your other modifications to reduce fuel consumption.  We have teamed up as an affiliate with FuelSaver-MPG to offer you a complete line of quality EFIE devices.